Thread-cutting mechanism for sewing machines



A- R. WOOD .Aug. 26, 1947 THREAD CfiITING MECHANISMS EOR SEWING MACHINESFiled Aug. 21, 1945 3 Sheets-Sheet l 1% m 3. cj zfrd 71/0060 Guam;

A. R. WOOD 2,426,543 THREAD CUTTING MECHANISMS FOR SEWING MACHINES FiledAug. 21,1945 3 Shgets-She'et '2 Aug. 26, 1947. R. WOOD ,42

I THREAD CUTTING MECHANISMS FOR SEWING MACHINES K Filed Aug. 21, 1945 3Sheets-Sheet 3 Patented Aug. 26, 1947 THREAD-CUTTING MECHANISM FORSEWING MACHINES Alfred E. Wood, Bridgeport, Cnn., assignor to The SingerManufacturing Company, Elizabeth, N. J a corporation of New JerseyApplication August 21, 1945, Serial No. 611,723

This invention relates to group-stitching sewing machines, such forexample as buttonhole machines or tacking machines, and moreparticularly to the thread-cutting mechanism of the machine, whichmechanism is designed not only to cut the needle-thread close to thework at the end of a sewing operation and hold the beginning end of theneedle-thread for the beginning of the next sewing operation, but alsoto retrim the beginning end of the needle-thread close to the work, sothat both ends of the needle-thread will be uniformly trimmed.

In sewing machines of the type to which the present invention pertains,it is customary to provide the upper member of the work-clamp with acombination thread-cutting and -nipping blade which is actuated at theend of the sewing operation to cut and nip the needle-thread. Thisthread-cutting and -nipping blade holds the beginning end of theneedle-thread during the sewing of slightly more than half of thestitching cycle. As the sewing proceed to complete the operation andnears the starting point, this blade is retracted to get it in readinesst0 cut the needle-thread after the stitching cycle is completed. Whenthe blade is retracted, however, it releases the beginning end of theneedlethread which, in view of its length, is in a position to besewed-in or bound down by the final stitches of the buttonhole or tack.In view of this condition, there is a certain lack of uniformity in theproduct of such a machine result ing from the fact that the beginningend is not disposed of and may at times protrude to an unsightly extentnecessitating hand retrimming.

To eliminate the necessity of this hand retrimming, the combinationthread-trimming and -nipping blade is operated twice for each completestitching cycle, once before the sewing is completed, preferably afterslightly more than one-half of the stitching cycle is completed, when itis safe to release the beginning end of the needle-thread, and a secondtime after the sewin is completed. The first operation of the bladeretrims the beginning end of the needle-thread and the second operationtrims the finishing end of the needle-thread; both ends being thusuniformly trimmed close to the work.

In prior machines, the resetting of the trimmer-blade preparatory to thefinal threadcuttin and -nipping operation is efiected by utilizingsolely the longitudinal shifting of the workclamp relative to the bed ofthe machine to bring the usual trimmer-blade retracting pushrod carriedby the work-clamp into contact with 14 Claims. (Cl. 112252) a fixedabutment member. Inasmuch as the longitudinal shifting of the work-clampis effected in a step-by-step manner, the resulting relatively slowretraction of the trimmer-blade in a plane perpendicular to the path ofneedlereciprocation requires that the trimmer-blade be swung beyond therange of the needle before the work-clamp is shifted to a point suchthat collision can occur between the needle and trimmer-blade. Thiscondition limited the capacity of the machine, since it prevented themachine from producing buttonholes or tacks smaller than a certain size.In an effort to increase the capacity of the machine, the length of theneedlethread trimmer-blade was reduced, but this introduced thepossibility of the trimmer-blade missing the needle-thread when it wasswung to trim the finishing end of the needle-thread.

It is the primary object of the present invention to provide meanseffecting a rapid retraction of the combination needle-thread-trimmingand -nippin blade for the purpose of resetting the blade for its finalthread-cutting and -nipping operation.

Another object of the invention is to provide a needle-thread-trimmingand -nipping blade retracting mechanism designed to operate with suchrapidity that the blade may be swung into its reset position after theblade has been shifted Within the range of the needle.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations, and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodimom; of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the drawings,

Fig 1 is a fragmentary right side elevational view of a straightbuttonhole sewing machine equipped with the present invention.

Fig. 2 is a top plan view, partly in section, of the bed of the machineshown in Fig. 1, illustrating the location of the thread-trimming deviceand the operating mechanism therefor when the machine is performing thefirst portion of the stitching cycle. I

Fig. 3 represents an enlarged vertical sectional view takensubstantially along the line 3-3, Fig. 2, showing the way in which theneedle-thread beginning end isheld nipped.

Fig. 4 represents a top plan View, partly in section, of theneedle-thread trimmer, illustrating the trimmer-blade in set positionpreparatory to the retrimming of the beginning end of the needle-thread.

Fig. 5 represents a vertical sectional view similar to Fig. 3, butshowing the relatively long released beginning end of the needle-thread.

Fig. 6 is a view similar to Fig. 5, but showing the needle-threadbeginning end retrimmed to its final short length.

Fig. '7 is a view similar to Fig. 4, but showing the trimming-blade inits reset position preparatory to its final thread-cutting and -nippingoperation.

Fig. 8 represents an enlarged perspective view of the cam-elementemployed for actuating the trimmer operating mechanism so as to swingthe trimmer-blade into its set and reset positions.

Fig. 9 represents an enlarged perspective view of the cam-locking diskwhich is employed for securing the actuating cam-element in any one of aplurality of selected positions determined by the. length of thebuttonhole or tack to be produced.

Fig. 10 represents an enlarged vertical, sectional View takensubstantially'along the line l@--lil, Fig. 1.

Fig. 11 represents an enlarged left side elevational view of thetrimmer-blade retracting pushrod and its latching expedient.

In the preferred embodiment of the invention, the buttonhole sewingmachine illustrated in the drawings comprises a frame including a bed isupporting a standard 2 of an overhanging bracket-arm terminating in ahead 3. Mounted in the head 3 is a vibratory gate 4 carrying an endwisereciprocatory needle-bar 5 fitted at its lower end with an eye-pointedthread-carrying needle 9. The needle-bar 5 derives its reciprocationfrom the usual actuating connections within the head 3, whichconnections are operated from the mainor arm-shaft (not shown) of themachine. The arm-shaft is connected by a vertical shaft l and gearing 8to a loop-taker shaft 9 adapted to carry at its outer end a rotaryloop-taker (not shown) for cooperation with the needle 9 in theformation of stitches.

The work W to be buttonholed is adapted to be held in a work-clampcomprising the usual lower work-plate ill and an upper clamp-foot I I.The upper clamp-foot H is carried by the two resilient arms i2 and i3which are secured at their inner ends on a yoke M pivoted at I5 to a lugIt upstanding from the longitudinal slideplate ll. The upper clamp-footH is yieldingly urged downwardly into contact with the lower work-plateIll by a coil-spring l8. To provide for separating the upper clamp-footll from the lower work-plate IQ for the insertion and removal of work,the yoke I4 is formed with a rearwardly extending tail-lever l9 adaptedto underlie a roller (Fig. 2) carried intermediate the ends of amanually actuated lever 2i fulcrumed at one end on a stud 22 threadedinto the supporting bracket 23. At its other" end, the lever 2| isfitted with a horizontally disposed stud 24 to the free end of which isattached a suitable treadlechain connection-element 25. Depression of asuitable foot-treadle will cause the lever 2! to swing on the stud 22,against the action of a spring 26, thus causing the roller 29 to engagethe tail-lever l9 and swing the yoke l4 about its fulcrum l5, therebyraising the arms [2 and i3 and the upper clamp-foot II.

To eifect shifting of the work relative to the endwise reciprocatory andlaterally vibratory needle 5, the work-clamp is'slowly moved instepby-step fashion, first away from the standard 2 and then towards thestandard to cause the first and second rows of side zigzag stitches tobe laid side by side in the work. The work-clamp derives itsstep-by-step movements from the usual feed-cam 2'! carried on aVertically disposed feedshaft'28 journaled in the bed and the bracketarmof the machine. The connections between the work-clamp and the feed-camare identical with those disclosed in my co-pending applicationSerialNo. 545,035, filed July 15, 194A. 'The feed-cam 21 and the feed-shaft 28are intermittently rotated by means of a one-way-acting clutch 29, ofthe well-known Horton type, which clutch is driven during the operationof the machine by means of an actuating lever 36 connected by a link 3!to a rock-lever 32 carried by the lower end of a vertically disposedrock-shaft 33 (Fig. 1) journaled in a bearing bushing 34 pressed intothe machine-bed I. At its upper end, the rock-shaft 33 has secured to ita second rock-lever 35 connected to a pitman 39 which embraces aneccentric 31 fast on the vertical shaft 1. As the shaft 1 is rotated,the eccentric 31 imparts to the rock-shaft 33 oscillatory movementswhich, through the rock-lever 32, link 3i and actuating lever 36,operate the clutch 29. The

clutch drives the feed-cam 21 and the feed-shaft 28 intermittently inone direction.

The needle-thread trimming and nipping mechanism now to be describedcomprises a trimming-blade 38 and a nipping-blade 39 (Figs. 3 and 6),the shanks of which are secured by a screw 49 in a cross-slot llprovided in a head 42 formed at the lower end of the usual verticalrock-shaft 43 journaled in the upper clamp-plate II. This constructionis substantially the same as that disclosed in the U. S. patent of E. E.Allen, No. 885,310, dated April 21, 1908. The needle-thread trimming andnipping-blades 38 and 39 are adapted to operate in a slot 44 defined bythe under surface 45 of the upper clamp-plate H and the surface 46 of ahardened detachable section 41 secured to'the clamp-plate H. Thenipping-blade 39 cooperates with the surface 15, as shown in Fig. 3, tohold the beginning end of the needle-thread during the sewing of thefirst portion of the buttonhole. The trimmer-blade 38 has a sharpenededge which cooperates with an edge of the surface 45 of the detachablesection 41 in severing the needle-thread.

The trimmer-blade carrying rock-shaft 43 has fixed on its upper end arock-arm 49 connected to the outer end of a trimmer-blade actuatingmember or retracting push-rod 49 disposed in the direction of thelongitudinal travel of the workclamp and endwise slidably supportedadjacent its inner end in an upstanding ear 55 integral with a plate 51secured by screws 52 on the yoke M. The ear 5!], in addition to servingas a support for the push-rod 49, also functions in conjunction'with afixed collar 53 and resilient pad 54 on the push-rod 49 as a stop tolimit the endwise movement of the push-rod under the action of acoil-spring 55 acting between the ear 50 and another fixed collar 56 onthe push-rod 49. The coil-spring 55 normally functions to maintain theparts in the position shown in Figs. 2 and 3, in which position thebeginning end of the needlethread is nipped and the resilient pad 54 ofthe collar 53 is against the ear 50.

To produce the necessary endwise movement of the push-rod 49 foractuating the threadtrimming and nipping blades 38 and 39 to effect therelease of the nipped beginning end of the needle-thread and to set thetrimmer-blade preparatory to the retrimming of the beginning thread-end,there is provided. a cam-actuated linkage. This linkage comprises alever 51 pivoted at one end on a stud 58 threaded into a lateralextension 59 provided on the supporting bracket 23. The other end of thelever 51 is upturned, as at 99, to engage a block 6| (Fi 4) adjustablysecured on the push-rod 49. The lever 51, intermediate its ends, isconnected by a link 62 to a second lever 63 pivoted at 34 on the lateralextension 59 and having a cam-follower nose 65 which is maintained by aspring 66 in contact with an actuating cam 6'! integral with anactuating device or cam-element 61 mounted on the feed-shaft 28. Theactuating cam 81 is formed with a gradual rise 68' terminating in asharp drop-01f 69; the timing of the drop-off 69 being regulated throughthe medium of a timing pin 19 adapted to be yieldingly pressed into aselected one of a number of timing holes H provided in a disk 12 fast onthe feed-shaft 28. On the rim of the disk 12, each of the timing holes7! is identified by a number from one to thirteen, corresponding to asimilar number employed on the adjusting device of the mechanismconnecting the feed-cam 21 with the work-clamp, which number indicatesthe length of buttonhole to which the machine is adjusted to produce.For a disclosure of this adjusting device, reference may be had to myabove mentioned co-pending application Serial No. 545,035. To efiect anadjustment of the timing of the cam 6'! to con-- form with an adjustmentof the work-clamp shifting mechanism, the cam-element 67' is lifted byits knurled hub 13, in opposition to a coil-spring M (Fig. 1), andturned relative to the feed-shaft 28 until the pin 79 is in registerwith the desired timing hole H, after which the knurled hub 13 isreleased. The coil-spring M maintains the pin 19 in the selected timinghole H, thus locking the cam-element 61' to turn with the feedshaft 28.

When the machine isstarted, the component parts of thread-trimmingmechanism are in the position shown in Fig. 2, with the beginning end ofthe needle-thread held nipped as shown in Fig. 3. As the sewingprogresses down the first side of the ibuttonhole, the feed-shaft 28 isturned slowly, causing the gradual rise 68 of the cam 67 to swing thelever 51, through the lever 53 and link 62, so that its upturned end 99engages the block 6! on the push-rod 49 and shifts the latter into theposition shown in Fig. 4. In this position of the push-rod 49, thetrimmer-blade 38 and the nipping-blade 39 have been swung into openposition, in which position the beginning thread-end is released asshown in Fig. 5, and the trimmerblade is set for its retrim stroke. Asthe machine continuesto operate, the cam 61 is turned to the point whereits drop-off 69 passes the nose 95 of the lever 63. When this occurs,the coil-spring 55 snaps the push-rod 49 endwise and in a direction toclose the trimmer-blade 38 upon and retrim the beginning end of theneedlethread to the length clearly shown in Fig. 6.

To provide for reopening or resetting the trimmer-blade 38 preparatoryto the trimming of the finishing end of the needle-thread and nippingthe beginning end of the needle-thread for the beginning of the nextsewing operation, I have provided a second cam-actuated linkage or leverarrangement, the components of which are designed and proportioned toperform its intended function rapidly and efficiently. To this end, the

cam-element 61 is provided with a second actuating cam 15 adapted toengage-a cam-followernose 16 formed on the free end of one of the armsof a two-arm lever 11 fulcrumed at 18 on the machine-standard 2. Theother arm of the lever 11 has secured to it a roller 19 arranged toenter an elongated slot 89 formed in the shorter limb of an L-shapedlever 8| fulcrumed at 58 on the lateral extension 59 of the supportingbracket 29. The longer limb of the lever 8| terminates in a downturnedend 82 adapted to be moved into engagement with the block BI on the endof the push-rod 49. As will be seen in Fig. 4, the cam '15 is positionedrelative to the cam 61 so that shortly following the action of thetrimmer-blade 38 in retrimming the beginning end of the needlethread,the cam 15 engages the nose 16 of the two-arm lever 11 and swings saidtwo-arm lever about its pivot 18. The longer arm of the twoarm lever,being operatively connected to the shorter limb of the L-shapedlever 8|,efiects a rapid turning of said L-shaped lever, bringing the downturnedend 82 thereof into engagement with the block 6|, thereby shifting thepush-rod 49 endwise against the action of the coil-spring 55 and intothe position shown in Fig. '7. In this position the trimmer and nippingblades 38 and 39 are open or reset preparatory to the final trimming andnipping of the needle-thread. As shown in Fig. '7, the trimmer andnippingblades 38 and 39 are maintained in reset position by alatch-lever 83 pivoted intermediate its ends at 84 on an upstandin ear85 formed on a bracket 89 fastened on the yoke [4 (Fig. 10). One end ofthe latch-lever 83 is biased, by a spring 81, downwardly to cooperatewith a stop-notch 88 formed in the collar 53 which is fixed on thepush-rod 49.

When the machine is started, the component parts of the thread-trimmingand -nipping mechanism are in the position shown in Figs. 2 and 10. Inthis position, the latch-lever 83 rests upon the push-rod 49 in advanceof the fixed collar 53. A the sewing progresses,.the cam 61 and itsassociated linkage operate to effect a release of the beginning end ofthe thread and to retrim the released thread-end to the desiredshort'length. As shown in Fig. 4, the extent of endwise movementimparted to the push-rod 49 to effect this thread-release and -retrim isjust short of bringing the stop-notch 88 on the fixed collar 54 intoregister with the latch-lever 83. Consequently, the latch-lever does notpreclude the proper functioning of the mechanism for this operation.Immediately after the retrim of the released thread-end is accomplished,the cam 15 and its associated linkage operate to reset the trimmer-blade38 preparatory to its final thread trimming and -nipping operation. Asshown in Fig. 7 the extent of endwise movement imparted. to the push-rod49, in opposition to the coilspring 55, is quite sufficient to move thestopnotch 88 on the collar 53 into register with the latch-lever 8-3,permitting the latch-lever under the action of the spring 8! to dropinto the notch 88 and lock the trimmer-blade and nipping-blade in resetposition.

Means actuated by the work-clamp lifting mechanism are provided foreffecting a release of the trimmer-blade 38 and nipping-blade 39 at theend of the buttonholing cycle. Referring to Figs. 1, 2 and '7, it willbe seen that the stud 24 carried by the manually controlled work-clampelevating lever 2|, and to which the treadle chain is connected, extendsthrough a cam-slot,

lie-formed adjacent the :upper end of an intermediate member orrock-lever 9i] pivoted at 9| on the machine-bed l. The rock-lever 90 hasconnected to it a link 92 having adjustably secured on it a trip-element93 adapted to cooperate with the latch-lever 83 to lift the same out ofthe notch 88 when the foot-treadle is depressed to elevate thework-clamp. As shown in Figs. 1 and 2, the link 92 is also connected toone limb of a bell-crank lever 94 disposed beneath the bed I; the otherlimb of the bell-crank lever being connected to a cross-slide 95 havinga rack 96 in mesh with a segmental gear 91 carrying a bobbin-threadtrimmer-blade 98. A copending application Serial No. 611,725 filedherewith discloses and claims the constructive features of theillustrated bobbin-thread trimmer. The connections above describedfunction simultaneously to operate both the needle-thread trimmer andthe bobbin-thread trimmer. It will be appreciated that the cam-slot 89,in its preferred form, is provided with an actuating portion 89 and adwell-producing portion 89" so that the link 92 is actuated only duringthe initial depression of the Work-clamp elevating foot-treadle andduring the time that the stud 24 is tracking the actuating portion 89,to insure that both of the sewingthreads are out before the work-clampis raised to release the work. The trip 93 is adjustably fastened on thelink 92 so that the timing of the release of the latch-lever 83 can beregulated. Also, the link 92 is preferably made adjustable, as shown at99 in Figs. 1 and 2, in order to provide'means for simultaneouslyregulating the timing of the actual thread-severing of both of thethread-trimming mechanisms.

From the above description taken in connection with the accompanyingdrawings, it will be appreciated that I have invented an improvedmeansfor effecting a rapid resetting of the needie-thread trimmingandnipping-blade preparatory to its final thread-trimming and -nippingaction. The design of the improved means is such that its quick actionis inherent. In addition, th cam for actuating the improved means isset" so that it does not function until the stitches forming the returnside of the buttonhole are being produced. This is desirable for thereason that'during the formation of the stitches on the return side ofthe buttonhole,

the work-clamp is moving toward the standard of the'machine, while thefree end 82 of the lever 81 is moving away from th standard toward theapproaching work-clamp. This simultaneous movement of the Work-clamp andlever toward each other augments the inherent quick action of myimproved resetting means, the result of which is an extremely rapidretraction of the trimmer-blade, whereby collision between thetrimmer-blade and the needle is avoided when a long trimmer-blade isemployed and the machine is set to sew short buttonholes approximatel /4in length.

Having thus set forth the nature of the invention, what 'I claim hereinis:

1'. In a group-stitch sewing machine, in combination, stitch-formingmechanism, a traveling work-clamp, a needle-thread-cutting and -nippingdevice, actuating means therefor includ ing a reciprocatory elementsupported by and normally partaking of the movements of the work-clamp,a first means comprising a cam actuated linkage adapted for engagementwith said-reoiprocatory element and effective for opening and thenclosing said' thread-cutting and -nipping device to release and thenretrim the beginning end of the needle-thread, a second means comprisinganother camactuated linkage adapted for engagement with saidreciprocating element and effective for reopening said thread-cuttingand -nipping device preparatory to its final nipping and cutting action,and means for effecting a final closing of said thread-cutting and-nipping device to nip and sever the needle-thread at the completion ofthe sewin operation.

2. In a group-stitch sewing machine, in combination, stitch-formingmechanism, a traveling work-clamp, a thread-cutting device, actuatingmeans therefor including a reciprocatory element supported by andnormally partaking of the movements of the work-clamp, means adapted forengagement with said reciprocatory element and effective for moving saidthread-cutting device into open position, said means including a firstpivotally mounted lever having one of its ends disposed to engage andactuate said reciprocatory element, a second pivotally mounted leveroperatively connected with said first lever, and means for actuatingsaid levers Whereby the first lever moves simultaneously with andopposite to the travel of said work-clamp in actuating saidreciprocatory element, and means for effecting a closing of saidthread-cutting device at a predetermined time during the groupstitchcycle.

3. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism adapted for interlocking an upper thread and alower thread, a work-clamp, means including a manually controlled leverfor opening said work-clamp for the insertion and removal of work, athread-cutting device for said upper thread and a thread-cutting devicefor said lower thread, a member movably mounted on said machine-frameand having a cam-slot, means on said manually controlled levercooperating with said cam-slot for imparting movement to said memberwhen said lever is actuated, and a connection with said member disposedto effect the operation Of both of said thread-cutting devices duringthe initial movement of said manually controlled lever and prior to theopening of said work-clamp.

4. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism adapted for interlocking an upper thread and alower thread, a work-clamp, means including a manually controlled leverfor opening said work-clamp for the insertion and removal of work, athread-cutting device for said upper thread and a thread-cutting devicefor said lower thread, a member movably mounted on said machine-frameand having a cam-slot provided with an actuating portion and adwell-producing portion, means on said manually controlled levercooperating with said cam-slot for imparting movement to said memberduring the traversing of the actuating portion of said cam-slot, and aconnection with said member disposed to effect the operation of both ofsaid thread-cutting devices during the actuation of said member.

5. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism adapted for interlocking an upper thread and alower thread, a work-clamp, means including a manually controlled leverfor opening said Work-clamp for the insertion and removal of work, athread-cutting device for said upper thread and a thread-cutting devicefor said lower 9 thread, a member movably mounted on said machine-frameand having a cam-slot provided with an actuating portion and adwell-producing portion, means on said manually controlled levercooperating with said cam-slot for imparting movement to said memberduring the traversing of the actuating portion of said cam-slot, aconnection with said member disposed to effect the operation of both ofsaid thread-cutting devices during the actuation of said member, andmeans for simultaneously regulating the timing of the thread-severing ofboth of said thread-cutting elements.

6. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism adapted for interlocking an upper thread and alower thread, a Work-clamp, means including a manually controlled leverfor opening said work-clamp for the insertion and removal of work, athread-cutting device for the upper thread and a thread-cutting devicefor the lower thread, a member movably mounted on said machineframe andhaving a cam-slot provided with an actuating portion and adwell-producing portion, means on said manually controlled levercoopcrating with said cam-slot for imparting movement to said memberduring the traversing of the actuating portion of said cam-slot, aconnection with said member disposed to effect the operation of both ofsaid thread-cutting devices during the actuation of said member, andmeans for regulating the time of thread-severing of one of saidthread-cutting devices relative to the time of thread-severing of theother of said thread-cutting devices.

7. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism, a work-clamp, means including a manuallycontrolled lever for opening said work-clamp for the insertion andremoval of work, a thread-cutting device, means for opening saidthread-cutting device, a latch for maintaining said threadcutting devicein open position, a member movably mounted on said machine-frame andhaving a cam-slot provided with an actuating portion and adwell-producing portion, means associated with said work-clamp openingmeans and cooperating with said cam-slot for imparting movement to saidmember during the traversing of the actuating portion of said cam-slot,and a connection with said member disposed to trip said latch during theactuation of said member whereby said thread-cutting device is releasedto close into effective thread-severing position.

8. In a group-stitch sewing machine, in combination, a machine-frame,stitch-forming mechanism adapted for interlocking an upper thread and alower thread, a work-clamp, means including a manually controlled leverfor opening said work-clamp for the insertion and removal of work, athread-cutting device for said upper thread and a thread-cutting devicefor said lower thread, a member movably mounted on said machine-frameand having a cam-slot provided with an actuating portion and adwell-producing portion, means On said manually controlled levercooperating with said cam-slot for imparting movement to said memberduring the traversing of the actuating portion of said cam-slot, saidactuating portion of the cam-slot being disposed so that said member isshifted the full extent of.

its movement before said work-clamp is opened sufficiently to free theWork, and a connection With said member disposed to eifect the operationof both of said thread-cutting devices during the actuation of saidmember. s;

9. In a sewingmachine, in combination, stitch; forming mechanism, aworkc1amp,j feeding means for relatively moving the'stitch-forming;mechanism and the work-clamp to sew a group of stitches, said feedingmeans including an actuating feed-shaft, a needle-thread-cutting and-nip-;- ping device, an actuating member operatively associated withsaid needle-thread-cutting and- -nipping device, a first meansactuatedfrom said feed-shaft for engagement with said actuating memberfor opening and closing said thread-cutating and -nipping device torelease and then-re-- trim the beginning end of the needle-threadjasecond means also actuated from said feed-shaft for engagement with saidactuating member for reopening said thread-cutting and -nipping devicepreparatory to its final nipping and cutting action, and meanspermitting a final closing of.

said thread-cutting and -nipping device to nip and sever theneedle-thread at the completion of the sewing operation. i

release and then retrim the beginning end o f'the needle-thread, asecond means adapted to engage said actuating member for reopening saidthread-T; cutting device preparatory to its final nipping, a d cuttingaction, a single actuating'device secured. on said feed-shaft foroperating said firstandf second means in series, and means permittinga,final closing of said thread-cutting and .-'nipping device to nipand'sever the needle-thread at the,

completion of the sewing operation.

11. In a sewing machine, in combination,"

stitch-forming mechanism, a work-clamp, feeding means for relativelymoving the stitch-forming mechanism and the work-clamp to sew a group ofstitches, said feeding means including a feed-shaft and connections forvarying the extent of the relative movement between the stitchformingmechanism and the work-clamp, a needle-thread-cutting and -nippingdevice, an actuating member operatively associated with saidneedle-thread-cutting and -nipping device, a first means adapted toengage said actuating member for opening and closing said thread-cuttingand -nipping device to release and then retrim the beginning end of theneedle-thread, a second means adapted to engage said actuating memberfor reopening said thread-cutting and -nipping device preparatory to itsfinal nipping and cutting action, an actuating device for operating saidfirst and second means in series, means for regulating the effectiveposition of said actuating device to conform with the selected positionof adjustment of the connections for varying the extent of relativemovement between the stitchforming mechanism and the Work-clamp, andmeans for permitting a final closing of said thread-cutting and -nippingdevice to nip and sever the needle-thread at the completion of thesewing operation.

12. In a sewing machine, in combination, stitchforming mechanism, awork-clamp, feeding means It for relatively moving: me stitch-formingmedia nism and the work-clamp to sew a group of stitches, said feedingmeans includingan actuating feed-shaft, a needIe-thread-cutting and-nipping device, anactuating member operatively associated with saidneedle-thread-cutting and nipping device, afirst' means adapted toengage said actuating member for opening and closing said threadcutting. and -n ippin'g device to release and their retrim the beginningend of the needlethread, a} second means adapted to engage saidactuating member for reopening said-thread-cutting device-preparatory toits final nipping and cutting action, anactuating device secured onsaidfeed-shaft and having a plurality of cam-- sections disposedtooperate said first and secand means in series, and means permitting afinal closing of said thread-"cutting and -nipping device to nip andsever theneedle-thread at the completion of the sewing operation. 7

1-3. In a; sewing machine, stitch-forming mechanisi-n, a work-clamp,feeding means for relatively moving the stitch-forming mechanism and thework-clamp to sew a group of stitches,- said feeding means including afeedsh'af-t and connections for varyingthe extent of the relativemovement between the stitch-formmg mechanismand the work-clamp, aneedletliread cutting' andf -nipping device, an actuating memberoperatively associated with said ne'e'd1e opening and closing saidthread-cutting and -nipping device to release and then retrim thebeginning end of the'needle-thread, a second means adapted to engagesaid actuating member for reopening said thread-cutting and -nippingdevice preparatory to its final nipping and cutting action, anactuatingdevice provided with a plurality of cam-sections disposed to operatesaid first" and second means in series, said actuating device beingmounted on said feed-shaft and secured thereto by means permittingregulation of the effective position of said cam-sections to incomblnation,

, thread-cutting and -nipping device, a first means 1 adapted" to engagesaid actuating member for conform with the selected position ofadjustment of the connections for varying the extent of relativemovement between the stitch-forming mechanism and the Work-clamp, andmeans for permitting a final closing of said thread-cutting and-nippingdevice to nip and sever the needlethreadat the completion of thesewing operation.

14. In a group-stitch sewing machine, in combination, stitch-formingmechanism, a traveling Work-clamp, a thread-cutting device, an actuating member operatively associated with said thread-cutting device andsupported by the normally partaking of the movements of the workclamp,means adapted for engagement with said actuating member and eftectivefor moving said thread-cutting device into open position, said meansincluding a first pivotally mounted lever having one of its endsdisposed to engage and operate said actuating member, a second pivot--al1y mounted lever connected to said first lever,-

and a cam device engaging said second lever in a manner to move saidlever simultaneously with and opposite to the travel of said work-clampin operating said actuating member, and means for effecting a closing ofsaid thread-cutting device at a predetermined time during the machinecycle.

ALFRED R. WOOD.

REFERENCES orrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name 'Date 1,920,944 Wood Aug. 1, 19331,955,994 Wood Apr. 24, 1934 1,404,727 Allen Jan. 31, 1922 1,325,707Wood Deck 23, 1919 1,369,371 Allen Feb. 22, 1921 1,912,056 Almond et al.May 30, 1.933 1,930,637 Allen Oct. 17, 1933 1,016,027 Mills Jan. 30',1912

